Matrix array programs using Java Script

Let assume we have an array of size 3 by 3 means 3 rows and columns
example

1 2 3
4 5 6
7 8 9

In this tutorial, we will learn about how to get the sum of elements that are placed in a different scenarios like the sum of elements in diagonal, last rows, last columns, and so on.

Sum of left diagonal elements

var i,j,s;
s=0;

for(i=0; i<2; i=i+1){
	for(j=0; j<2; j=j+1){
		if(i==j){
			s=s+x[i][j];
		}
	}
}
document.write("Sum of left diagonal elements of a matrix:"+s+"<br>");

Sum of right diagonal elements

var i,j,s;
s=0;

for(i=0; i<2; i=i+1){
	for(j=0; j<2; j=j+1){
		if(i+j==2){
			s=s+x[i][j];
		}
	}
}
document.write("Sum of right diagonal elements of a matrix:"+s+"<br>");

Sum of lower elements of diagonal in a matrix

var i,j,s;
s=0;

for(i=0; i<2; i=i+1){
	for(j=0; j<2; j=j+1){
		if(i>=j){
			s=s+x[i][j];
		}
	}
}
document.write("Sum of lower elements of left diagonal of a matrix:"+s+"<br>");